Snap switch



Oct. 29, 1946.

P. G. FRERER` SNAP SWITCH. Filed July 28,1944

ATTORNEYS Patented ci. 29, 1946 SNAP SWITCH Paul G. Frerer, Milwaukee,- Wis., assignor `to .Perfex Corporation, ration of Wisconsin Milwaukee, Wis., a corpo- Application July 28, 1944, Serial No. 547,020

11 claims. (c1. 20o-67) This invention relates in general to switching mechanisms, and more particularly to snap action switches of the self-contained or enclosed type. The primary object ofthis invention is to provide a snap switch construction which is simple and dependable and which may be manufactured economically.

A further object of the invention is the provision of a snap switch mechanism which is readily adjustable after assembly so as to obtain optimum switching action.

Other objects will appear from the following description and appended claims.

For a full disclosure of the invention, reference is made to the following detailed description and to the accompanying drawing, in which, y Fig. 1 is a top View, with the cover` removed, of one form of snap switch embodying the invention; y l

VFig. 2 is a side view, partly in section; and

Fig. 3 is a view similar to Fig. 2 of a modification.

Referring to the drawing, reference character I indicates a base member forlthe snap switch unit. This base -member is of `elongated rectangular shape andV is provided with transverse holes 2 andl 3 which are adapted to receive mounting screws. Preferablymoulded in the base member is a terminal bushing 4 which is screw-threaded to receive a terminal screw 5. This bushing extendsthrough the base member and at its upper end supports a contact stud 6 which carries a stationary contact 1. The contact stud 6 is screwthreaded in the terminal bushing and is formed with a hexagonal socket 8 which is adapted to receive a Wrench which may be inserted through the open end of the bushing 4 when the contact screw is removed. Y

Located on the other end of the base member is a second terminal bushing 9- which may be identical with the bushing 4.- This bushing 9 receives a terminal screw I0 at its lower end and a contact stud II at its upper end. The contact stud II is identical with the contact stud 6 and may be adjusted by a wrench inserted through the terminal bushing 9. i

Supprted .on the upper face of the base I is a U-shapedbracket I4. This bracket consists of a base portion I5.and a pair of ears |16 and I1 (Fig. 1) which extend outwardly from the base. The base portion of the bracket I4 may be secured to the base I by means of staking to a central terminal bushing I8. This terminal bushing receives a terminal screw I9. The bracket I4 may b eadditionally secured `to the basel by ascrew 55 2 2D which extends upwardly through the base and which is threadedinto the base portion I5 of the bracket.;` i

Extending between the ears I6 and I1 of the bracket I4 is a pivot pin 22. This pivot pin supports a rocker member generally indicated as 23. This'rocker member is formed with a pair of downwardly extending ears 24 and with outwardly-extending arms 25 and 26. Attached to the mid-portion of the rockermember between the ears 24 is a spring blade 21 which carries movable contacts 28 and 29 at its two free ends. The arms 25 and 2S of the rocker member are ofi-set adjacent the movable contacts so as to provide portions 30 and 3l which are adapted to engage the rear of movable contacts 28 and 29. These off-set portions are formed with openings 33 and 34 (Fig. 1) through which the spring blade 21 extends. These openings are wider than the thickness of the spring blade 21 and permit'l a limited amount of motion of the ends of the spring blade relative to the arms 25 and 26.

The bracket I4 also supports a second pivot pin 36. This pivot pin carries a leaf spring 31 which bears against an upward extension 38 on the rocker member 23. This leaf spring 31 is actuatedk by a plunger 39 which extends through. the cover 40 of the switching mechanism.

The left hand leg 26 of the rocker member is formed to provide an armature which cooperates with a U-shaped permanent magnet 42 which is received in a `cavity formed in the base member I. This permanent magnet is held in place by an extension of the base portion I5 of bracket I4. I When no pressure is applied to the plunger 39, the permanent magnet 42 causes the parts to assume the positions shown in Fig. 2. Thus the magnet has pulled the rocker member 23 in a counterclockwise direction which causes the movable contact 28 to engage contact 1. At this time the right ,hand end of the leaf spring 21 is engaged by the bottom of the opening 34 in the rocker member, which insures that the movable contact 29 is disengaged from its corresponding stationary contact.

`When pressure is applied to the plunger 39 it bows the leaf spring 31 and applies a downward force to the right hand end of the rocker member 23. This force acts in opposition to the attractive force of the permanent magnet 42. As

the force on the plunger 39 is increased, a point will be reached at which the spring 31 overcomes the attractive force of the armature 42. The rocker member 2,3 will now snap to its clockwise position in which the contact 29 engageslcontact by the attractive force of the magnet 42. 'When this point is reached the rocker member 23 will snap in the counterclockwise direction, thereby disengaging contact 29 from contact Il and engaging contact 23 with contact 1.

It will be noted that when the contact 28 is in engagement with the contact 1 the portion 39 of the rocker member is in engagement with the rear face of contact 28. By this arrangement stationary contact 1 acts as a positive stop to the counterclockwise rotation of the rocker member. Thus adjusting of the contact stud 6 in the terminal bushing 8 provides an adjustment for the lspacing between the armature portion 26 and the permanent magnet 42. As this spacing is decreased, the attractive force of the armature increases. This attractive force determines theamount of force that must be -applied to plunger 39 in order to operate the switch. This attractive vforce may be adjusted so as to obtain the desired degree of snap action by turning the contact stud 6V in bushing 4. This may be done by removing thelterminal screw and Vinserting a' hexagpnal Wrench through the terminal bushing;

VIt is also desirable to provide an adjustment for the gap between the contacts when open. It is necessary for this gap to be Wide enough to insure a positive separation of the contacts. At the same time itis desirable to limit this gap as much as possible, as this reduces the amount of work required tooperate the switch. This contact gap maybe adjusted by rotating the contact stud Il in the terminal bushing 9. This is preferably done by inserting a tool through the outer end of the terminal bushing.

In the arrangement shown in Fig. 2 theswitch is pperated in one directionk by pushing plunger ilin, and is operated in the other direction by permitting the plunger' to move outwardly. In

operate with'a push-pull action. In other words,

ated position until the plunger is actually pulled wardlyt This action may be obtained by the arrangement shown in Fig. 3. In this figure the construction of Fig. 2, except for the plunger 50 a'- d Itheinclusion of an extra permanent magnet 51.*" The permanent magnet 5I is -held in place by secured to the -base I by means of a screw 53. The

which is attached by a link 55 to the spring blade 31.

plunger 50 has been pulled to its'outermost position. The armature portion 25 is now closer to tion 2dV is to magnet 5I. The attractive force of magnet 42 is therefore greater than the attracsorne applications vit is desirable to have the switch it is desirable t0 `have the switch remain in actuou-t.' instead of simply being allowed to move outconstruction is substantially identical with the an extension 5 2 of the bracket base l5 which is plunger 5i! is formed with an enlarged head 54 With the parts in the positions shown, the

the permanent magnet 42 than the armature portive force of magnet 5I, and the rocker member 23 is therefore held in its counter-clockwise position in which the movable contact 28 engages statiqnary contact 1.v

'Whenthe plunger 50 is pushed inwardly, it applies a counter-clockwise force to the rocker memis applied to the plunger 50, this will be transinittcd ,through the spring 31, thereby applying 'a cpuriterfclockwisfe force to the rocker member 23. When this force, coupled with the attractive' force of magnet 42, becomes suicient to overcome the attractive force of magnet 5l, the rocker member will snap to its counter-clockwise position as shown.

` In Fig, 3 it wiil be apparent that adjustment of the contact stud-6 will determine the degree of inward force required on plungerE in order to operate the switch in one direction, `and that adjustment of the contact stud II will determine the outward force required on plunger 50 to operate the switch in the opposite direction.

From the foregoing it will be apparent that the present invention'provides a simple and positive snap switch construction. It -will also'be apparent that the present invention provides a construction which-may be 'readily assembled. It will be further Aapparent vthat the invention provides easily accessible 'adjusting means by which the switch may be calibrated -fo'r securing optimum switching action.

While Iihave shown and described only two forms of the invention, the construction may be varied considerably Without departing from the scope of Ythe invention. I therefore desire to be limited only by the scope of the appended claims.

What is claimed is:

fl. In a switch unit, a base, a switch arm on one side ofthe base and pivoted thereto, a movable contact operated by said switch arm, a stationary contact cooperating with said movable contact, adjusting means for 'the stationary con` tact', a terminal member having a screw hole for.

mounting 'a terminal screwon the other vside ofthe base7 the screw hole forthe terminal screw being iin alignment with the adjusting means for the stationary contact whereby the stationary Contact mayl Abe adj-usted by a tool inserted through said screw hole. v

2. In a's'witch unit, a base! a switch arm on one side of the base and pivoted thereto, a movable contact operated by Ysaid switch arm, a hollow terminal bushing extending throughY-thebase for mounting a terminal screw on the other side of the base, a stationary `contact screw threaded in the terminal bushing on said one 'side of the base, said stationary contact cooperating with said movable contact Aand Vbeing adjustable by means of a tool inserted through said hollow bushing..

`3. In-a-n' enclosed snap switch unit, a fbase,1a switch arm o n one side of the base and pivoted thereto, a cover for the snap switch unit, means extending through the ycover for actuating said switch arm, a movable contactactuat'ed b y said switch armg a permanent magnet secured tothe base, an armature coperatingrwith said mag-net for causing vnflovement of the movable contact with ysnap action, astationary contact-,cooperating with said `movable vcontact and forming a stop for limiting movement ofsaid armature with respect; to the-magna, adjusting means for the stationary contacta terminal member havnga screw hole forA mounting a terminal screw onthe other side ofthe Ibase,` the Vscrew hole for thel terminal screw being in alignmentfwith the ad-` justin'gmeafns for the stationary contact'whereby the stationary contact may be adjusted by a tool inserted through said screw hole. f

4.-In an enclosed-snap switch unit, a base, a switch arm on one side of the base and pivoted thereto, a cover for the snap switch unit, means extending through the cover for actuating said switch arm, a movable contact actuated by said switch arm, a permanent magnet secured to the base, an armature cooperating with said magnet for causing movement of the movable contact with snap action, a stationary contact cooperating with said movable contact and forming a stop for limiting movement of said armature portion with respect to the magnet, a hollow terminal bushing extending through the base for mounting a terminal screw on the other side of the base, said stationary contact being screw-threaded in the terminal bushing on said one side of the base and being adjustable by means of a tool inserted through the hollow bushing.

5. In a snap switch unit, a base, a pair of spaced stationary contacts secured to the base on one side thereof, a pair of movable contacts cooperating with said stationary contacts, a switch actuating member pivotally secured to the base at a point between the stationary contacts and adapted selectively to cause one of said movable contacts or the other to disengage its corresponding stationary contact, a permanent magnet secured to the base, an armature carried by said switch actuating member adjacent said permanent magnet, a pair of terminals mounted opposite the stationary contacts on the other side of the base, and independent adjusting means for each of said stationary contacts, said adjusting means being accessible through said terminals.

6. In a snap switch unit, a base, a pair of spaced stationary contacts secured to the base on one side thereof, a rocker member pivotally secured to the base at a point between said stationary contacts, spring blade means attached at a point between its ends to the rocker member adjacent its pivot, said spring blade means extending generally parallel with the base and having a movable contact adjacent each end thereof cooperating with a corresponding stationary contact, the rocker member comprising oppositely extending arms located between the spring blade means and the base, said arms extending perpendicular to the base adjacent the movable contacts and being formed with openings through which the spring blade means extends, the edges of said openings determining the limits of lost motion between the ends of the spring blade means and the rocker member.

7. In a snap switch unit, a base, Ia pair of spaced stationary contacts secured to the base on one side thereof, Ia rocker member pivotally secured to the base at a point between said stationary contacts, spring blade means attached at a point intermediate its ends to the rocker member adjacent its pivot, said spring blade means extending generally parallel with the base and having a movable contact adjacent each end thereof cooperating with a corresponding stationary contact, the rocker member comprising oppositely extending arms located between the spring blade means and the base, said arms eXtending perpendicular to .the base -adjacent the movable contacts and being 'formed with peningsthrough" which the spring blade means extends, the edges of said openings determiningthe limits of`lost motion between the ends ofthe spring blade means and the rockermember, vsaid rocker member being formed with an arma-ture portion `between the spring blade means and the baseal permanent magnet secured to the base adjacent said armaturelportiom and .a resilient actuator for applying force to saidV rocker member,

8. In a snap switch unit, a base, a pair of spaced stationary contacts secured to the base on one side thereof, a rocker member pivotally secured to the base at a point between said stationary contacts, spring blade means attached intermediate its ends to the rocker member adjacent its pivot, said spring blade means extending generally parallel with the base and having a movable contact adjacent each end thereof cooperating with a corresponding stationary contact, the rocker member comprising oppositely extending arms located between the spring blade means and the base, said arms extending perpendicular to the base adjacent the movable contacts and being formed with openings through which the spring blade means extends, the edges of said'openings determining the limits of lost motion between the ends of the spring blade means and the rocker member, said rocker member being formed with an armature portion on each side of its pivot, a rst permanent magnet secured to the Ybase adjacent -one armature portion, a second permanent magnet secured to the base adjacent the other armature portion, and a resilient actuator for applying force to said rocker member.

9. In a snap switch unit, a base, a pair of spaced stationary contacts secured to the base on one side thereof, a rocker member pivotally secured to the base at a point between said stationary contacts, spring blade means attached intermediate its ends to the rocker member adjacent its pivot, said spring blade means extending generally parallel with the base and having a movable contact adjacent each end thereof cooperating with a corresponding stationary contact, the rocker member comprising oppositely extending arms located between the spring blade and the base, said arms extending perpendicular to the base adjacent the movable contacts and be- 50 ing formed with openings through which the spring blade means extends, the edges of said openings determining the limits of lost motion between the ends of the spring blade means and the rocker member, said rocker member being 55 formed with an armature portion between the spring blade means and the base, a permanent magnet secured to the base adjacent said armature portion, a resilient actuator for applying force to said rocker member, and means for in- 60 dependently adjusting said stationary contacts. 10. In a snap switch unit, a base, a stationaryT contact secured to the base, a rocker member pivoted to the base, ya spring blade carried by said rocker member and extending generally parallel 65 with the base, said spring blade carrying a movable contact adapted to engage the stationary contact, the rocker member including an armature portion extending generally parallel with the base between the spring blade and the base, 70 the rocker member also including a portion extending perpendicular of' the base adjacent the movable contact and being formed with an opening through which the spring blade extends, the edges of the opening determining the limits of 75 lost motion between the free end of .the spring portiqn, and e ,resilient lfe..ela 1:240,01*.exteenldmaker membe.

11. In a snap swith unit, .e baise, a ,stetimery 5 Contact secured ,'to the basefa braliet mounted on the base and having ears extending outwardly fmmthe base, .a rst pivot pin extending between the ears of said braket, a IQker .member @2S- tending generally parallel @f -the hase and pivoted 10 eperetine with ead. stetieeary @meet and e, 1.11 ated hy `seid reeker member. Sleep Y, meen? .associated withy seid rocker member, answered @webv pm earned. by Seid, bracket, e lee@ Springpveted on seid second pivot pin. end enges-ine seid rocker member, and en eetueter bearing against said leaf SPI'lllg PAUL Cr. 

